Pneumatic spring.



B. W. DAVIS.

PNEUMATIC SPRING.

APPLICATION FILED NOV. 15, 1906.

Patented Sept. 7, 1915.

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BENJAMIN WALTER DAVIS, Ol? PHILLIPS, WISCONSIN.

PNEUMATIC SPRING.

Specification of Letters Patent.

Patented Sept. '3, 1915.

Application filed November 15, 1906. Serial No. 343,574.

To all whom it may concern:

Be it known that l, BENJAMIN WALTER DA-vIs, a citizen of the UnitedStates, residing at Phillips, in the county of Price and State ofWisconsin, have invented certain new and useful Improvements-inPneumatic Springs, of which the following is a specification.

My invention relates to pneumatic springs;

and has for its object to provide an improved resilient support orspring which may be used as a substitute for the ordinary steel springsin those places where such springs are commonly used. Thus, I may use myimproved spring as a resilient support for automobiles, carriages,bicycles or other vehicles, and as a resilient support for chairs,cushions or mattressesin fact, it is capable of general application.

With these and other objects, which will hereinafter appear in view, myinvention consists in the combinations and vinafter set forth andclaimed.

Tn the accompanying drawing-Figure l is a transverse sectional elevationof one form of my improved spring. Fig. 2 is a similar view showing amodified form of the device.

In the accompanying drawing, in Fig. 1, ll have shown my improved springas a vehicle support, such as a support for automobiles, carriages orother vehicles, or as a support for a chair or other seat. In thisfigure or represents a substantially globular bag of flexible materialand a an outer covering of leather or similar material therefor. At itsupper end this globular bag is connected to the head 7) of a bolt 6. Anysuitable fastening means may be used for this purpose. I have shown awire 6 which, when tight ened, serves to draw the edges of the bag intothe grooved portion of the bolt head. This bolt 6 is attached to a partc which may represent the body of a vehicle, or car, or a seat. At itslower end the outer cover of the globular bag is secured in a similarmanner to a neck f on a base f. This base f may represent part of theunderframe of an automobile or carriage, or the supporting stand of achair. Wires f serve to secure the outer portion of the globular bag tothe neck. This neck is provided with and an elongated neck a of theinner bag extends through this passageway. A metallic lining e, having aflanged end a serves details herea passageway,

to secure the lower portion of the inner bag to the neck i the lower endof this lining being screw threaded to receive a nut e Connected to thelower end of this metallic lining is the neck 6 of a relief chamber 6,and a check valve 6 permits the passage or air from the globular bagthrough the lining e and neck e to the relief chamber. This reliefchamber may be formed with walls of flexible material or unflexiblematerial, as may be desired. The check valve a, while permitting thepassage of air from the globular chamber to the relief chamber, preventsits return from the relief chamber to the globular chamber. A passagewayc, however, connects the relief chamber with the neck 6 The passageway eis of such size inrelatio'n to the passageway 6, e 9 as to permit a lessquantity of air in a given time to pass back from the relief chamberthan passes, from the globular chamber to the relief chamber-that is tosay, while the passage of air from the globular chamber is comparativelyunrestricted, the return of air to the globular chamber is restricted. Aclamp e surrounds the passageway 6 the. walls of which are flexible, anda screw c operates this clamp so as to regulate the return of air, whichmay be restricted more or less as desired. A covering d, which may be ofmetal, if so desired, surrounds the upper portion of the globularchamber and flares downwardly and outwardlyas clearly shown in Fig. 1.To the lower edge of this covering is connected a flexible cover 01' ofleather or light material, this leather covering being secured to themetallic covering by wires a at its upper edge and to the neck f at thebase by wires f The operation of my device is as follows: When weight issupported upon the spring, the globular bag tends to flatten out,resting. at its lower portion upon the base f, the upper portion of suchglobular bag engaging the walls of the covering d. Thus, as the weightsupported by the spring increases, the supporting area of the spring iscome spondingly increased. If the spring is subjected to sudden shocks,the air therein will be forcibly expelled through the unrestrictedpassageway c, e and permitted to enter the relief chamber e. Owing toits restricted return, however, the sudden return of the spring ispreventedon the contrary, the return is made easy and gradually.

Thus, the great objection to pneumatic springs of this type isovercome,--that is, the excessive vibration thereof. It will beunderstood that the air in the relief chamber e is kept at any desiredpressure and serves to maintain the pressure in the spring.

In Fig. 2 I have shown my spring as applied to a bicycle seat support.In this case 9 represents the seat stem which is longitudinally mountedin a neck f attached to the upper half 7 of a globular chamber, thelower portion f being attached to the seat support. Within this globularchamber,-the walls of which are rigid, I mount the globular bag a as inthe form described above. The cover (1 in this instance is in the formof a flat plate, and the leather covering 61' is secured between thewalls f, f, of the globular chamber. The relief chamber 6 in this caseis in the form of a long tube extending down into the seat support andthe valve between the spring and the relief chamber is shown at 6 beingprovided with a restricted passageway c. It will be understood that whenthe valve is removed from its seat by the downward pressure of the airin the spring an unrestricted flow is permitted from the spring to therelief chamber, while the return of air from the relief chamber to thespring is only through the restricted passage 6 The operation of thisform of spring 1s substantially the same as of the first described. Whenweight is applied to the bicycle seat, the tendency of the spring is toflatten out, the lower portion being supported upon the wall f of theglobular chamber, while the upper portion has an extended bearing on thecover 0!, thus increasing the area of support as'the weight increases.If desired I may provide a re stricted passage for the air in bothdirections, as will be readily understood.

The operation of my improved device will be understood without furtherdescription.

I claim 1. A pneumatic spring comprising a substantially globular fluidretaining chamber having flexible walls, curved means engaging theflexible walls of the retaining chamber to increase the'supporting areathereof at a predetermined rate when weight is applied thereto, andmeans for connecting said chamber to two relatively movable membersbetween which the chamber is interposed.

2. A pneumatic spring comprising a substantially globular fluidretaining chamber having flexible walls, rigid means engaging theflexible walls of the fluid retaining chamber adapted to distribute theload when weight is applied thereto, and means for connecting saidchamber to two relatively movable members between which the. chamher isinterposed.

3'. A pneumatic spring comprising a flexi-- ble-.fluid retainingchamber, means for connecting said chamber to two relatively movablemembers respectively, means whereby the supporting area of the chamberis increased as the weight thereon is increased, means for quicklyrelieving the chamber of a portion of the fluid therein, and means forgradually restoring the fluid to the fluid chamber. v

4. A pneumatic spring comprising a flexible fluid retaining chamber,means for connecting said chamber to two relatively movable membersrespectively, means whereby the supporting area of the chamber isincreased as the weight thereon is increased, a fluid relief chamberconnected to the retaining chamber, and means for controlling the flowof fluid from the relief chamber to the retaining chamber.

5. A pneumatic spring comprising a flexible fluid retaining chamber,means for connecting said chamber to two relatively movable membersrespectively, a relief chamber connected to the fluid retaining chamber,and rigid means engaging the walls of the retaining chamber when weightis applied thereto.

6. A pneumatic spring comprising a substantially globular fluidretaining chamber having flexible walls, means for connecting saidchamber to two relatively movable members respectively, a reliefchamber, a passageway between the fluid retaining and relief chambers,means providing for the unrestricted flow of fluid from the fluidretaining chamber to the relief chamber and for a restricted return flowfrom the relief 8. A pneumatic spring comprising a substantiallyglobular fluid retaining chamber having flexible walls, rigid bearingmembers engaging said, walls above and below respectively when saidspring is subject to a load, and means for fastening the upper and lowerparts of said chamber to said rigid members respectively.

; 9. A pneumatic spring comprising a substantially globular fluidretaining chamber having flexible. walls, ri id means engaging theflexible walls of the uid retaining chamber adapted to distribute the.load, and

screws having flanges adapted to engage the u per and lower sides ofsaid chain er and cure same against the said rigid means re spectively.

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10. A pneumatic s ring comprising a submeans for connecting said casingto the two stantially globular uid retaining chamber relatively movablemembers between which having flexible walls, means for connecting saidchamber is interposed.

said chamber to two relatively movable BENJAMIN WALTER DAVIS.- 5 membersbetween which the chamber is in- Witnesses:

terposed, a telescopic protecting casing sur- W. T. JoNEs,

rounding said fluid retaining chamber, and ANNA L. SAvomf

